I have a strong hive that just swarmed. The varroa count on my bottom board went from inconsequential (2-3 day) to >100 immediately after the swarm.

The change was rapid, within days. Anyone else experience this irruption of the mite at the swarm event. Does this have something to do with the enormous cohort of brood that accompanied the swarm. Just before the swarm, I had capped brood over the center frames of 2 deep and 1 medium. Does the varroa count sometime decline, or is this change an inevitable upward transition.

The hive had been stocked with a Minnesota Hygenic queen in summer '09. At this point, I am not sure who is queen (unmarked, and I don't search her out).

What are my treatment options for this hive? I am at peak honey flow (Eucalyptus). Can I extract the spring surplus, and then do Oxalic vapor in mid-May as the summer dearth transitions.

I haven't used Oxalic before. How stressful is it on a summer hive? Seems to me you would have to repeat the treatment at half brood cycle periods, since the oxalic won't touch capped brood in my (limited) understanding. That seems to require 3 treatments spaced at about 10 days to clear the emerging new brood. That is a lot of intervention, if the Oxalic is semi-toxic to the bees themselves.

I did use home-made "wintergreen oil" and Crisco patties in the summer of 2008. I discontinued this after losing 2 hives. I felt the wintergreen was stressing the hives to the point of decline. The treatment may have been overused as I left the patties on for >6 weeks-- and I note recent prescriptions for commercial patties are for more limited treatment periods (one brood cycle and during fall resting periods). In 2009, I invested in Minnesota Hygenic queens, and was really happy with the nearly complete absence of Varroa.

I would be interested in hearing from the annual treatment cycle of coastal California keepers, as I think mild winter may have a slightly different set of treatment periods. The annual peak of Varroa appears to come in late August-September, there is pretty substantial coastal scrub bloom in this period (buckwheat) and a lot of late honey is made. The real dearth is October-December.

.It is easy now to kill mites from the swarm. You may use oxalic acid, thymol or formic acid. OA trickling is the most easy.

One way is to give a larva frame. Just before capping mite go into the larva cell. When All has capped, you may kill the brood. But it is wastefull to the colony. One full frame of brood means 3 frames of bees.

Then let brood emerge in the brood hive. Mites will be free and when they have not larvae in capping stage, they will be free. Now you can kill free mites easily as said above.

If you put the larva frame over the excluder, the queen cannot make more brood there and you may limit the destroy of brood.

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It belongs to the procedure that after one week you make from brood hive a false swarm. When flying bees have separated to the own hive, then give an oxalic acid treatment.